Chapter 5- Cladistics Flashcards Preview

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Flashcards in Chapter 5- Cladistics Deck (13):

How can evidence of a species which are part of a clade be obtained?

From the base sequences of a gene or the corresponding amino acid sequence of a protein


Species that have recent common ancestors can be expected to have what?

Few differences in a base or amino acid sequence


What does the fact that sequence difference accumulate gradually affect?

So there is a positive correlation between the number of differences between two species and the time since they diverged from a common ancestor


What can be used as a molecular clock?

There is evidence that mutations occur at roughly constant rate so they can be used as a molecular clock


What are two things traits can be?

Analogous or homologous


What are homologous structures

are similar because of similar ancestry; for example chicken wing, human arm and other forelimbs


What are analogous structures

Similar because of convergent evolution- the human eye and octopus eye show similarities in structure and function but they are analogous because they evolved independently


What are cladograms

Tree diagrams that show the most probable sequence of divergence in clades


Cladograms are based on what?

Based on base or amino acid sequences


What are the branching points on cladograms called?



What does evidence from cladistics show

That classification of some groups based on structures did not correspond with the evolutionary origins of a group of species


What were the 5 clades that had been incorrectly combined into one family in the figwort family

1) two small families were merged with the figwort family
2) nearly 15 genera have been moved to plantain family
3) about 12 genera of parasitic plants have been moved to the boomrape family
4) 13 genera have been transferred to a newly- created family , the lindernia family
5) two genera were moved to the newly created family, the calceolaria family


What is a clade?

A group of organisms that have evolved from a common ancestor

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